Impaired thermoregulation and thyroid function in iron-deficiency anemia

Article Abstract:

Iron deficiency is a significant problem in much of the world, with up to 15 percent of the world population having the condition. Poor thermoregulation, control of body temperature, is one of many consequences of iron deficiency, and it is possible that metabolism of thyroid hormone and catecholamines, adrenalin-like hormones made by nerves, may be associated with deficient thermoregulation. The relationship between thermoregulation and metabolism of these hormones was evaluated in 10 women with iron-deficiency anemia, 8 nonanemic women who had low iron levels, and 12 healthy women. Core body temperatures were lower in anemic subjects after exposure to moderately cool water for 100 minutes, and iron supplementation improved the ability of these subjects to maintain body temperature. By contrast, iron-depleted subjects had a higher core temperature than the other subjects, before or after iron supplementation. All subjects increased the metabolic rate, measured as oxygen consumption, in response to cool water baths. However, anemic women had a much lower metabolic rate than controls, both before and after iron supplementation. Iron-depleted nonanemic women had higher metabolic rates, which decreased to near-normal levels after iron supplementation. Presumably related to this were the lower thyroid hormone (TH) levels of anemic subjects; following iron supplementation, the levels rose significantly but were still lower than control levels. Iron-depleted women had near-normal TH levels, but these decreased after iron supplementation. In contrast, levels of adrenalin and noradrenalin did not vary appreciably among the groups. The study indicates that poor thermoregulation accompanies iron deficiency anemia, and this is likely related to changes in thyroid hormone metabolism, while catecholamines do not appear involved in this process in humans. (Consumer Summary produced by Reliance Medical Information, Inc.)

Body temperature, Body temperature regulation, Thyroid hormones, Iron deficiency anemia

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Tyrosine- and phenylalanine-restricted formula diet augments immunocompetence in healthy humans

Article Abstract:

Restriction of certain amino acids, tyrosine and phenylalanine, in the diet may improve immune function in such a way that an individual with cancer is resistent to tumor growth and metastasis (spreading of cancer cells). In rodents with different forms of cancer, tumor growth rate was reduced, metastasis was inhibited, and survival improved on such a diet. Restriction of tyrosine (Tyr) and phenylalanine (Phe) is still experimental in human cancer patients, but two studies have reported tumor stabilization or remission in patients with malignant melanoma. The effect of Tyr and Phe restriction on immune function in nine healthy adults was studied. Because Phe and Tyr are amino acids found in many proteins, the subjects consumed a diet consisting of only low-protein foods, plus a supplemental formula that provided all the other amino acids and various nutrients needed for a normal, adequate diet. The regimen, followed for four weeks, was associated with significant increases in the numbers of immune cells known as natural killer, T helper, and T cytotoxic/suppressor lymphocytes. The activity of natural killer cells also rose in most subjects. In addition, platelet aggregation decreased in most subjects. Both decreased platelet aggregation and increased natural killer cell activity appear to inhibit tumor growth and metastasis. The study should be considered preliminary because of the small number of subjects, but it did show significant improvements in immune function and also demonstrated that the use of a Phe- and Tyr-restricted formula diet is feasible. Such a diet regimen could be combined with cancer chemotherapy if further research confirms these beneficial effects. (Consumer Summary produced by Reliance Medical Information, Inc.)

Measurement, Cancer, Blood platelets, Diet therapy, Killer cells, Amino acids, Tyrosine, Phenylalanine

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